A Kurdish fighter from the People's Protection Units (YPG) fires heavy machine-gun at Islamic State militants in Raqqa, Syria June 21, 2017. (Reuters photo)

DAMASCUS, June 30 (Xinhua) -- The defeat of the Islamic State (IS) in Iraq will surely empower the Syrian army in its own battles against the terror group in Syria, if the U.S. stops placing snags in Syrian forces' progress, according to a Syrian analyst.

Previously known as the Islamic State in Iraq and the Levant, before shortening the name to the Islamic State only as its followers were dreaming of expanding beyond the two countries, the terror-designated group is losing its original cradle in Iraq.

In the face of the wide-scale offensive of the Iraqi forces and the Hashid Shaabi paramilitary forces, the self-declared caliphate in Iraq has almost fallen in its last stronghold in the Iraqi city of Mosul.

A day earlier, Iraqi Prime Minister Haider al-Abadi declared that the capture of the famous al-Nuri Mosque marked an end to the IS self-proclaimed caliphate in Iraq.

"We are seeing the end of the fake Daesh state. The liberation of Mosul proves that," al-Abadi said on Twitter, using the Arabic acronym for IS.

"We will not relent. Our brave forces will bring victory," he added.

However, the situation in Iraq is different from that in Syria, as all of the forces fighting IS in Iraq, including the U.S.-led anti-terror coalition, are on the same page.

In Syria, there are several forces fighting IS but they hold enmity toward one another, which constitutes a big obstacle to the victory in Syria.

The U.S.-led coalition in Syria is backing the Kurdish-led group of the Syrian Democratic Forces (SDF), which is launching an offensive on Raqqa, the de facto capital of IS in the country.

The SDF has made notable gains in Raqqa, managing to lay siege to the entire city after capturing neighborhoods on the eastern and western flanks of it.

Further to the north, Turkish-led Free Syrian Army (FSA) rebels fought against IS and captured areas in the northern countryside of Aleppo over the last few months.

To the south, the Syrian army captured key areas and almost ended the presence of IS in the southern countryside of Aleppo and large swathes of the Syrian Desert all the way to the Iraqi borders.

But the three forces hold enmity toward one another, as the Turkey-backed rebels are bracing for offensives against the SDF positions in a border area called Afreen in northern Syria, since Turkey wants less Kurdish influence near its borders with Syria.

Meanwhile, the U.S. shot down a Syrian warplane over Raqqa recently under the pretext that it was threatening the SDF, which released a statement and accused the Syrian army of attacking its forces, while pledging retribution.

The differences among those powers are expected to be more obvious in the post-IS era, but for now, the IS presence in Syria is dwindling.

While the SDF is fighting in Raqqa, the Syrian army and allied fighters are moving to eliminate the terror group in areas under its control in the eastern province of Deir al-Zour near Iraq.

The battle of Deir al-Zour is expected to be larger than that of Raqqa, as the terror group holds significant sway in the countryside of the province and is currently besieging the city which is under the government control.

On top of that, all the IS fighters fleeing Raqqa or Iraq are taking positions in Deir al-Zour.

In order to reach Deir al-Zour and break the IS siege, the Syrian army needs to keep advancing in the desert in the eastern countryside of Homs Province in central Syria and to fortify its positions near the Iraqi borders.

But the move seems not to resonate with Washington, as it also has bases near the Iraqi borders and apparently wants to curb the influence of the Iranian support to the Shiite fighters in Syria and Lebanon, through Iraq.

The Syrian army was struck several times by U.S. warplanes when it was advancing in the desert, close to the Tanf border crossing with Iraq, where the U.S. and Britain have military bases and are training Syrian rebels, as cutting Iran's support from Syria and Hezbollah in Lebanon is part of the U.S. and Israel's plan.

However, the Syrian army managed recently to challenge the red lines drawn by the U.S. and reached the Iraqi borders, where the Syrian forces and the Shiite-led Hashid Shaabi forces met.

Of course, the Syrian progress came with the support of Hezbollah and the Russian air force, which raised the ire of the United States.

Over the past few days, the U.S. administration started to float talks about information it has on the Syrian government's preparations to use chemical weapons against the rebels, promising a powerful response.

The Syrian government slammed such accusations as "baseless allegations," noting that the U.S. hopes to use the same pretext to strike the Syrian army as in April when it launched a surprise missile attack on an air base in Syria without carrying out any investigation.

Experts in Syria say playing the chemical weapons card is U.S. warning to both Russia and Syria not to cross red lines, or areas the U.S. considers places of its own interests.

Osama Danura, a Syrian political analyst, who holds a PhD in political science and served as a member of the Syrian government delegation to the Geneva talks, told Xinhua that the Iraqi victory against IS will surely reflect positively on the Syrian military progress if it wasn't hindered by the United States.

"The Iraqi and Syrian fronts in fighting IS are integral and cannot be separated and you cannot defeat IS in Iraq without defeating it in Syria," he said.

The main characteristic of the terror group is the ability to act or react quickly by moving its military gears from one place to another and it can use the Syrian territories as a base to empower itself and launch offensives in Iraq again, if it wasn't defeated in Syria at the same time, according to the Syrian expert.

He said the void left by IS should be immediately filled by the legitimate military forces of the two countries.

Danura said the Syrian army will move to liberate the city of Bukamal and Deir al-Zour in eastern Syria to "end the presence of the most dangerous terror organization in the region, if it wasn't hindered by America."

"We see that the American side is trying to start a new chapter of the chemical weapons play and it's also trying to hinder the efforts of the Syrian army to fight IS," he said.

"All of this indicates that the United States doesn't want to easily let go of IS as its using the presence of this group in Syria to practice pressure on the Syrian government," Danura added.